Genotypic and environmental effects on chromosomal abnormalities in hexaploid triticale grown in southern Brazil and correlation between meiotic behavior and fertility of progenies
1991
Falcao, T.M.M. (Federal University of Rio Grande do Soul-UFRGS, Porto Alegre (Brazil). Departament of Genetics)
Four triticale lines were analyzed and the occurrence of univalents and laggards chromosomes, condensation disturbances, chromosomal breaks, bridges, and micronuclei in pollen quartets were observed. Comparison between mother plants and means of their progenies showed significant correlation values for characteristics such as univalents at metaphase I (r = 0.96, P less than 0.05), laggard chromosomes at anaphase I (r = 0.86, P less than 0.05), and micronuclei in pollen quartets (r = 0.86, P less than 0.05), indicating the role of genotype on this kind of abnormal chromosome behavior. The correlation values were not significant for chromosomal breaks (r = 0.60), condensation disturbances at metaphase I (r = 0.50), and chromosomal breaks at telophase I (r = 0.37), indicating higher environmental influence on these chromosomal abnormalities. The Meiotic Index, which represents the percentage of pollen quartets with less than 10 per cent of abnormalities, showed no significant correlation (r = 0.35) when compared to grain fertility of other spikes from the plants analyzed. However, the Meiotic Index of analyzed plants and the mean grain fertility of their progenies were significantly correlated (r = 0.93, P less than 0.01). These results suggest that chromosomal unbalance at meiosis may not be critical for grain formation, perhaps because of buffering effect of polyploidy, but becomes critical in the next generation, by affecting the fertility of the progenies
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